Brain versus gut: Our inborn food fight

The relatively larger human brain makes us the most intelligent of the primates. But if we’re so smart, how come we’ve eaten our way into an obesity epidemic?

One reason is the relatively smaller human stomach and shorter large intestines, says Emory anthropologist George Armelagos.

“Our evolutionary history has given us a brain that is focused much of the time on eating, and a gut that isn’t designed for today’s variety and volume of high-density food,” explains Armelagos, a bioarcheologist and an expert in prehistoric diets.

Armelagos recently wrote a review of research on evolution and the human diet, published in the Journal of Anthropological Research.

Journalist Michael Pollan popularized the concept of “the omnivore’s dilemma,” the desire for dietary variety paired with the perilous search for new foods, in his best-selling book by the same name. Pollan primarily covered how today’s abundance of food is fueling a national eating disorder.

Armelagos focuses on the prehistoric perspective. “Our current pattern of eating reflects the way in which Homo sapiens evolved and resolved the omnivore’s dilemma,” he says. “Our cravings for certain foods don’t go back just a few years, or even 10,000 years, but more than a million years."

For thousands of millennia, our ancestors subsisted as foragers, hunting and gathering in marginal environments. The expansion of the brain’s neocortex in early humans facilitated social cognition and memory, supporting the task of finding edible plants and prey amid the vagaries of an unpredictable climate.

Larger brains, however, increased caloric demands: The human brain, which represents only 2 percent of our body mass, consumes 20 percent of our energy. Around two million years ago, Armelagos says, our early ancestors began evolving a smaller total gut size, relative to other primates.

“The expensive-tissue hypothesis argues that our big brains are fueled by the energy saved by our having a smaller stomach and shorter large intestines,” he says. “Whatever the reasons for the changes in the alimentary canal, there is no question that they necessitated diets of high-quality, high-density foods.”

Fast-forward through millennia to the development of agriculture, cooking, the industrialization of food, and finally the advent of McDonalds. Today we’re faced with a perfect storm that’s capsizing the nutritional benefits of our adapted biology, Armelagos says.

“If you study our primitive pasts, the biological underpinnings of today’s obesity epidemic become clear,” Armelagos says. “But a solution to this complex bio-cultural problem is not so clear.”

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Is that latte worth $4? You better believe it.

By Carol Clark

For years, I’ve stayed loyal to my cell phone: a basic candy bar model. Cheap. Great reception. Easy. Which explains why I was naïve enough to think I could go to the Apple store yesterday and pick up an iPhone 4. The hundreds of geeks who brought lawn chairs and books for the line snaking through Lenox Mall made it clear I was a novice at technical self-indulgence. So I went downstairs to Starbucks to console myself with a latte.

I checked my email and saw this article from U.S. News and World Report on 10 things to splurge on this summer (including an iPhone 4 and a trip to Starbucks for the new free wi-fii.) Validation of your purchases, and attempted purchases, is what you need when you’re sipping a $4 coffee.

What really drove it all home for me was the message from an Emory scientist quoted in the U.S. News article. Here's the excerpt:

Gregory Berns, a professor in the psychiatry and behavioral sciences as well as economics at Emory University, found that when people pay more for products that they believe enhance their mental acuity (such as coffee or energy drinks), then they are more likely to work. Berns identifies this as a "placebo" effect. Basically, it works because people believe it works. That means if you believe a $4 coffee will help you ace a test or perform well in an interview, then you should spend $4 on that coffee because it probably will help you.

"We have been conditioned to expect that higher prices equates to higher quality," explains Berns. "Therefore with a product like an energy drink, you expect the more expensive it is, the better it works."

But is a $4 coffee really better than a $1 one? It is if you believe it is, says Berns.

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'Hominid' a hit in Holland

Check out this Dutch news report, above, on the recent performances of "Hominid" at Holland's Burger Zoo. Theater Emory commissioned the play, which is based on chimpanzee behaviors observed by Emory psychologist Frans de Waal when he was a young researcher at the zoo. The video report is in Dutch, but the images give an idea of the elaborateness of the large, outdoor staging of the drama for its ongoing European tour.

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Both oil spill and clean-up pose health risks

Cleaning the Gulf oil mess "is very toxic work," warns Linda McCauley, dean of Emory's school of nursing. In the video above, McCauley discusses some of the human health concerns associated with the ecological disaster, from the physical effects of inhaling chemicals to depression.

You can listen to McCauley discuss more about potential psychological effects of the oil spill on Gulf coast residents in this WABE Atlanta report.

A nationally recognized environmental health researcher, McCauley is among the scientists participating in an Institute of Medicine workshop in New Orleans exploring the potential short- and long-term health impact of the nation's worst oil spill.

In the video below, she explains that the safety of the chemical being sprayed into the ocean to disperse the oil is debatable. "Dispersants help take off oil that's floating in water, but when you emulsify it, it sinks down in the water," McCauley says. "Environmentalists are very concerned about what's happening to the animal and plant life by sinking the oil to the bottom of the ocean."



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Computers breathe life into 'Toy Story'

From the zoetrope to the magic lantern and the 1937 Disney classic “Snow White,” animators have always pushed the boundaries of technology and art. For decades, the hand-drawn artistry of Disney Studios dominated animated feature films. But rapid advances in computer-generated imagery, better known as CGI, have revolutionized the field.

The 1995 film "Toy Story" was "a complete game changer,” says Eddy Von Mueller, an Emory lecturer in film studies. “Toy Story 3” opened in theaters today, to rave reviews.

“The Toy Story franchise is fun, because you can look at the three Toy Story films and you can see the evolution of CGI as a cinematic tool," Von Mueller says. “Toy Story proved that we could make animation via computers that audiences would respond to, and because of that the floodgates have opened.”

Disney eventually bought Pixar. “When Disney says we can’t beat them we better join them, it’s an acknowledgment that the world of animation has been overturned,” he says.

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Can whales and dolphins adapt to oily Gulf?

The dead sperm whale found this week in the Gulf of Mexico puts the spotlight on how the BP oil spill will affect this endangered mammal, along with other cetaceans, such as dolphins, that must break the oil-slicked surface to breathe.

“These communities of whales and dolphins are already known to be stressed, because they’re dealing with other pollutants, like heavy metals, in the water,” says Emory neuroscientist Lori Marino, an expert in whale and dolphin intelligence and behaviors. “They are already compromised animals, and when they have something like this to deal with, it can be a tipping point for them.”

NASA satellite image, below, shows oil reaching Alabama beaches and the Florida panhandle. (Click on image to enlarge.)
It is unknown whether the deaths of the young sperm whale and the half-dozen dolphins that have been found washed up on Gulf beaches are oil related. Unlike the stark visual evidence of birds with oil-coated feathers, the toxic impact on whales and dolphins is primarily internal.

“They have to open their blowholes to breathe,” Marino says. “Imagine sticking your nose in a bowl and snorting oil. You’d be choking.”

A greater, and more lasting, impact may be the domino effect of toxins in the food chain, as oil droplets get into the fish and squid that cetaceans eat, she says.

Recent reports of large numbers of dolphins moving into shallow waters off Florida to flee the oil are troubling, Marino adds. “If they stay in the shallows and the oil comes in after them, they’ll be trapped.”

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Bringing new blood to high school science

Murder or a grisly accident? Psychology grad student Sabrina Sidaras (on floor) helps high school students learn to think like scientists. Photo by Tiffany Smith.

Want to get the attention of 11th grade chemistry students on the first day of class? Then ask them to investigate a suspicious death in the lab. Set the scene, including yellow police tape, broken vials of chemicals, fake blood and a “corpse” splayed on the floor.

“The first time I did it, I broke a smile,” says Sabrina Sidaras, an Emory psychology graduate student who played dead at Cedar Grove High School. “I didn’t realize how funny the students would be.”

Sidaras joined forces with Cedar Grove science teacher Tiffany Smith last Spring for PRISM, a collaboration of Emory and Atlanta area schools. The program pairs Emory graduate students with middle school and high school teachers to develop and implement problem-based learning (PBL) and other innovative teaching techniques into science classrooms.

In the case of the body on the lab floor, the students have to deduce what killed the victim by observing the evidence. “The students love it,” Sidaras says. “They’re used to coming in a class and sitting down, but this presents them with a whole different experience. They get excited, talking to each other about what may have happened and doing an investigation.”

Click on comic to enlarge:
Neuroscience graduate student Kate O'Toole created a comic strip to introduce teens to her research of ion channels.

PBL lesson plans developed by PRISM have gripping names, like “Dial M for Molecule,” “Adding Fuel to the Fire,” “Fatal Attraction,” “Sealed with a Kiss” and “Got Gas?”

PRISM aims to first get the students interested, then help them learn the science and understand how it applies to real life. “I think it really opens their eyes,” Sidaras says.

The experience changed her perspective as well. Instead of following a traditional career path in academia, Sidaras now hopes to get a job developing high school science curriculums.

Qing Shao, a graduate student in biophysics, was paired with David Wetty, who teaches 10th-grade physics at South Atlanta High School. “He’s very dynamic, and he helped me become a better communicator,” Shao says. “I learned to be patient, and to explain things in a way that everyone can understand.”

When a student who used to sleep at the back of the class started paying attention, she knew she’d made a breakthrough. “He was actually very smart,” she says.
Tenth-grade students turned the periodic table into a rap song and video. Click here to see it.

PRISM lessons, which can involve anything from Spiderman to rap music, were a big culture shock for Shao, a native of China. “In China, you can have 70 students in a class,” she says. “Everybody is very quiet and never moves. The teacher writes things on the board and the students take notes.”

She says she enjoyed PRISM and problem-based learning as much as the high school kids. “In the future, if I get a chance to contribute something, maybe I can bring some PBL to China,” she says. “It’s really very fun.”

About 100 Emory students have participated in PRISM since the program began in 2003 through a National Science Foundation grant. Emory is applying for additional funds to expand the program, with a focus on teaching evolution.

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Sewage raises West Nile virus risk

More than 700 U.S. cities have combined sewer overflows, allowing wastewater to flow into urban waterways with minimal treatment. Video of an Atlanta CSO stream by Gonzalo Vazquez-Prokopec.

Sewage that overflows into urban creeks and streams during periods of heavy rain can promote the spread of West Nile virus, an Emory study finds.

The analysis of six years of data showed that people living near creeks with sewage overflows in lower-income neighborhoods of Southeast Atlanta had a seven times higher risk for West Nile virus than the rest of the city.

“The infection rate for mosquitoes, birds and humans is strongly associated with their proximity to a creek impacted by sewage,” says Gonzalo Vazquez-Prokopec, the Emory disease ecologist who led the study. “And if the creek is in a low-income neighborhood, we found that the entire cycle of infection is even higher.”

More affluent residents are more likely to have air-conditioning and use insect repellant and other protective measures, the researchers theorized.
Red outline shows Atlanta boundary: Click on graph to enlarge.

The study, to be published by Environmental Health Perspectives, was a collaboration of Emory, the Centers for Disease Control and Prevention, the Georgia Division of Public Health, the Fulton County Department of Health and Wellness, the National Institutes of Health, the Fogarty International Center and the University of Georgia.

According to the Environmental Protection Agency, about 850 billion gallons per year of untreated mixed wastewater and storm water are discharged into U.S. urban waters, mainly through combined sewer overflow (CSO) systems that are used in more than 700 cities. Under normal conditions, CSO systems channel wastewater to a treatment plant before it is discharged into a waterway. During periods of heavy rain or snowmelt, however, the wastewater flows directly into natural waterways after only minimal chlorine treatment and sieving to remove large physical contaminants.
Photos of Atlanta CSO streams, above and below, by Gonzalo Vazquez-Prokopec.

Most of the available data on the human health impacts of sewage-affected waterways focuses on the effects of exposures to bacteria, heavy metals, hormones and other pollutants.

Previous research by Emory’s Department of Environmental Studies has shown that the Culex mosquito – a vector for West Nile virus and other human pathogens – thrives in Atlanta streams contaminated with CSO discharges. The mosquitoes become more populous, breed faster and grow larger than those found in cleaner waters.

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“We wanted to know if the CSOs also raised the risk of getting infected with West Nile Virus,” said Uriel Kitron, chair of environmental studies and a co-author of the study.

An expert in geographic information systems (GIS) technology, Vazquez-Prokopec did a spatial analysis integrating the geographic coordinates of each CSO facility and associated streams, and six years of surveillance data on mosquito abundance and West Nile virus infections in mosquitoes, humans, blue jays and crows. (These birds are considered sentinels for the disease, due to their high West Nile Virus mortality and their proximity to humans.)

During 2001-2007, Georgia reported 199 human West Nile virus infections and 17 deaths. About 25 percent of the cases resided in Fulton County. The county forms the core of metropolitan Atlanta, and encompasses a range of socio-economic conditions, from the wealthiest neighborhoods in the state to those with the highest poverty rates in the country.

The analysis found that mosquitoes and birds near all seven of the CSO facilities and associated streams of Atlanta had significantly higher rates of West Nile virus infection than those near urban creeks not affected by CSOs. Humans residing near CSO streams also had a higher rate of infection if they lived in a low-income neighborhood with a greater proportion of tree canopy cover and homes built during the 1950s-60s. Residents of a wealthy northern Fulton County area did not experience an increase in West Nile virus cases, despite their proximity to two CSO streams.

In 2008, Atlanta completed an underground reservoir system designed to reduce the size and the number of CSOs. “In terms of mosquitoes, however, this remediation has the potential to make things worse instead of better by releasing slower flows of nutrient-rich effluent into streams,” Vazquez-Prokopec notes.

Emory scientists and public health officials are continuing to study West Nile virus and CSOs in Atlanta urban streams. Their goal is to help identify effective measures to limit the spread of the disease.

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Hugs go way back in evolution

Charles Q. Choi writes in Scientific American: Chimpanzees may comfort others in distress in ways very similar to how people do, according to what may be the largest study of consolation in animals by far. The new findings in our closest living relatives could help shed light on the roots of empathy in humans. ...

To better understand how empathy might have evolved in our lineage, animal behaviorist Teresa Romero of Emory University and her colleagues studied roughly 30 chimpanzees housed outdoors at the Yerkes National Primate Research Center. Over a span of eight years they documented cases where uninvolved bystanders offered comfort to recent victims of aggression. Whereas most studies on animal consolation typically involve looking into a few hundred cases of conflicts and their aftermaths, "ours is based on an analysis of about 3,000 cases," Romero says.

Read the full Scientific American article, and see the full details about the Emory study in the Proceedings of the National Academy of Sciences.

Photo, above, by Frans de Waal shows a young chimpanzee consoling an adult male that just lost a fight.

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How babies use number, space and time

A 9-month-old can make intuitive leaps across quantitative concepts, says Stella Lourenco, shown in her lab with research participant Beckett Ford. Photo by Kay Hinton.

By Carol Clark

Even before they learn to speak, babies are organizing information about numbers, space and time in more complex ways than previously realized, a study led by Emory University psychologist Stella Lourenco finds.

“We’ve shown that 9-month-olds are sensitive to ‘more than’ or ‘less than’ relations across the number, size and duration of objects. And what’s really remarkable is they only need experience with one of these quantitative concepts in order to guess what the other quantities should look like,” Lourenco says.

Lourenco collaborated with neuroscientist Matthew Longo of University College London for the study, to be published in an upcoming issue of Psychological Science.

In his 1890 masterwork, “The Principles of Psychology,” William James described the baby’s impression of the world as “one great blooming, buzzing confusion.” Accumulating evidence is turning that long-held theory on its head.

“Our findings indicate that humans use information about quantity to organize their experience of the world from the first few months of life,” Lourenco says. “Quantity appears to be a powerful tool for making predictions about how objects should behave.”

Lourenco focuses on the development of spatial perception, and how it interfaces with other cognitive dimensions, such as numerical processing and the perception of time. Previous research suggests that these different cognitive domains are deeply connected at a neural level. Tests show, for instance, that adults associate smaller numbers with the left side of space and larger numbers with the right.

“It’s like we have a ruler in our heads,” Lourenco says of the phenomenon.

Other tests show that when adults are asked to quickly select the higher of two numbers, the task becomes much harder if the higher number is represented as physically smaller than the lower number."It's like we have a ruler in our heads," Lourenco says. Photo by Carol Clark.

Lourenco wanted to explore whether our brains just pick up on statistical regularities through repeated experience and language associations, or whether a generalized system of magnitude is present early in life.

Her lab designed a study that showed groups of objects on a computer screen to 9-month-old infants. “Babies like to stare when they see something new,” Lourenco explains, “and we can measure the length of time that they look at these things to understand how they process information.”

When the infants were shown images of larger objects that were black with stripes and smaller objects that were white with dots, they then expected the same color-pattern mapping for more-and-less comparisons of number and duration. For instance, if the more numerous objects were white with dots, the babies would stare at the image longer than if the objects were black with stripes.

“When the babies look longer, that suggests that they are surprised by the violation of congruency,” Lourenco says. “They appear to expect these different dimensions to correlate in the world.”


The findings suggest that humans may be born with a generalized system of magnitude. “If we are not born with this system, it appears that it develops very quickly,” Lourenco says. “Either way, I think it’s amazing how we use quantity information to make sense of the world.”

Lourenco recently received a grant of $300,000 from the John Merck Fund, for young investors doing cognitive or biological science with implications for developmental disabilities. She plans to use it to further study how this system for processing quantitative information develops, both normally and in an atypical situation such as the learning disorder known as dyscalculia – the mathematical counterpart to dyslexia.

“Dyslexia has gotten a great deal of attention during the past couple of decades,” Lourenco says. “But as our world keeps getting more technical, and students in the United States lag other countries in math, more attention is being paid to the need to reason about numbers, space and time. I’d like to explore the underlying causes of dyscalculia and maybe get a handle on how to intervene with children who have difficulty engaging in quantitative reasoning.”

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Rappers find their elements

Does studying the periodic table of elements weigh you down? Then lighten up and think of it as a rap song. That’s what 10th grade students at Dekalb Early College Academy did, and the result (see video above) puts the “cred” in chemistry.

“Everyone who worked on it had a great time,” says Shannon Thorne-Brackett, the students’ physical science teacher. Thorne-Brackett was a 2009-2010 fellow of PRISM, a collaboration of Emory and Atlanta area schools. The program fosters scientific literacy in public school students using problem-based learning (PBL) and other innovative teaching strategies.

PRISM gave Thorne-Brackett license to open up the curriculum to songs, videos, poetry, drawings and other projects not normally associated with the physical sciences. “I let each student tap into their own way of learning,” she says. “It was scary, because we have ECOTs (end of course tests). Naturally, you just want to lecture the students about what they need to know to score well.”

Her efforts paid off. At the end of the Spring semester, 100 percent of Thorne-Brackett’s students passed the physical science ECOT, and 87 percent of them scored a 90 or above. “All of the students were fully engaged, and I had fun, too,” she says.

Thorne-Brackett was among the many faculty at Dekalb Early College Academy to lose their jobs to budget cuts recently. “I’m going to miss the kids a lot,” says Thorne-Brackett. Luckily, she will be taking her PBL skills to a new position, at Arabia Mountain High School.

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He did the math for his country

A bill in the Senate could open the door to the chance for Puerto Rico to become the 51st state. So where should we put the 51st star on the American flag?

Slate columnist Chris Wilson put the question to Emory mathematician Skip Garibaldi, who wrote a computer program for all possible combinations for flags of any number of stars. Slate used the code to make an interactive flag calculator:



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Obama urged to wean nation off oil

An oil-soaked pelican gets a bath in Fort Jackson, La. Photo by Justin Sumberg, U.S. Navy/Marine Photobank.

Cynthia Tucker writes an editorial in the Atlanta Journal-Constitution, calling for President Obama to lead the country down the path to alternative energy:

Obama should remind the country that if we don’t start to shift from oil now, in 50 years the entire Gulf coast may be a disaster area, permanently closed to beach-goers, bird-watchers and fishermen. He doesn’t want that for his daughters, and most Americans don’t want that for their children, either. He should also remind voters that the U.S. military has spent decades entangled in the troubled Middle East largely because of our dependence on petroleum.

“This is a chance to turn a tragedy into an opportunity,” said Drew Westen, Emory University psychology professor and expert on political communications. “Americans are really ready to hear that the way to end their dependence on foreign oil is to end their dependence on oil.”

There are signs that Obama is finally finding his voice. Speaking in Pittsburgh on Wednesday, the president vowed to “work with anyone from either party” to pass a bill that would support alternative fuels such as wind and solar energy. Top White House aide David Axelrod told me that Obama “believes strongly that the spill underscores the need to develop alternative sources of energy . . . There is heightened awareness that allows us to move forward this year.”

Read the full editorial.

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Summer illusion brings moon closer

During the summer, the moon plays an optical trick known as the Moon Illusion. As it rises in the east, it always appears larger and closer to us. Because the sun is so high, the moon has to hang low, as they are on opposite sides of the sky. Photo, below, by NASA.

Especially during the full moon cycle, the low-hanging moon appears huge. Cameras don't see the illusion, but our eyes do. NASA Science describes it this way: When you look at the moon, rays of moonlight converge and form an image about 0.15 mm wide in the back of your eye. High moons and low moons make the same sized spot. So why does your brain think one is bigger than the other? After all these years, scientists still aren't sure why. Read more about the Moon Illusion.

On June 4 and 5, the moon will also sound closer at Emory, when OurSong: The Atlanta Gay and Lesbian Chorus performs "Lunar Essence" at Cannon Chapel.

The concert celebrates the dark of the night during the brightest part of the year with music that uses stark imagery of the moon and how it affects the Earth. Selections range from the ever-popular "Moon River," to a song by New Zealand composer David Childs based on the Emily Dickinson poem "The Moon is Distant from the Sea." Tickets are $20 for the concert, which begins at 8 p.m.

Gulf oil mess fuels interest in green energy

Oil floats on the surface of the Gulf of Mexico. Photo: BP p.l.c.

“The spill in the Gulf, which is just heartbreaking, only underscores the necessity of seeking alternative fuel sources,” President Obama said in a recent speech.

As thousands of barrels of oil gush daily into the waters of the Gulf of Mexico, Emory inorganic chemist Craig Hill has been spending time in Washington, speaking about the University’s green energy research.

“The Gulf oil mess affects everybody,” Hill said. “I think there’s no question that it’s having a significant impact on how we view the risks for offshore drilling as we seek ever more fossil fuel.”

Louisiana beach clean-up, below. Photo by Patrick Kelly, U.S. Coast Guard/Marine Photobank.

On May 2, Hill addressed the Council of Scientific Society Presidents in Washington on his lab’s recent breakthrough in sustainable solar energy research. Work by Hill’s lab on water oxidation catalysis, a crucial component of converting solar energy into clean hydrogen fuel, was recently published in Science, and is the centerpiece of the Emory Bio-inspired Renewable Energy Center.

“Emory is becoming a focal point for a lot of interest in the efforts to confront the problems of fossil fuel consumption and global climate change,” Hill said. “Our team really does have the best water oxidation catalyst on the planet.”

Hill is back in Washington this week and next, for Department of Energy meetings on catalysis and solar energy.

Carol Browner, Obama’s top energy advisor, has called the Gulf oil gusher “probably the biggest environmental disaster this country has ever faced,” and the president is pushing Congress to pass a climate change bill this year.

“Federal funding is substantial for green energy, but it’s still far below what it should be,” Hill said. “Everything is pointing to the fact that we’re going to need alternative energy to power society. It’s really a global imperative that affects health and security worldwide.”

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